1. Field of the Invention
This invention relates to a method and apparatus for generating static electricity.
2. Description of the Prior Art
The electrode used in an apparatus which utilizes static electricity (for example, an electrostatic preciptator, an electrostatic coating apparatus, etc.) is usually of an exposed type. Consequently, there are problems associated with this type of electrode, such as a potential hazard, wear and corrosion of the electrode due to corona discharge, and so on.
The electrostatic electrode further has an ill effect in that the electrode can thereon accumulate electric charge as condensers do, and therefore it includes another difficulty that its surface area for electrostatic action is limited by the effect.
More particularly, any charge accumulated on an electrode may cause undesired discharge, even after high voltage applied to the electrode has been interrupted. In addition, the larger the surface area of the electrode, the stronger the discharge, since the amount of charge accumulated on an electrode is proportional to the surface area of the electrode.
For this reason, therefore, in an electrostatic coating apparatus for example, there has been a problem of accidental fire due to possible electric discharge toward the thinner or the like filling the job site.